Magnetic switch



Feb. 9, 1960 FlGl 4 H. G. SELLS 2,924,683

MAGNETIC SWITCH Filed Jan. 30, 1959 INVENTOR; HARRY G. SELLS ATTOR N EYUnited States Patent i MAGNETIC SWITCH Harry G. Sells, Columbus, Ohio,assignor of one-half to Vern E. Davis, Columbus, Ohio ApplicationJanuary 30, 1959, Serial No. 790,266

11 Claims. (Cl. 200-87) This invention relates to an electrical switchand more particularly to a magnetic switch of the type provided with anoverload protection device.

In general, the novel switch of this invention includes a pair ofmovable contacts for selectively applying a source of electrical energyto an external circuit. The movable contacts are carried by an armaturewhich is selectively disposed in one of two positions by a manuallyoperated actuator and is retained in the selected position by apermanent magnet.

An overload protection device is electrically connected in series withthe load circuit and is adapted to break the electrical connection inthe event an overload or short circuit occurs in the load circuit.

This unique switch is actuated with a minimum of effort and is silentduring said actuation. The switch can be compactly constructed, and itscomponent parts are relatively inexpensive to manufacture. As such, thespace requirement for its installation is insignificant and its initialcost for such installation is relatively small. The switch is readilyadaptable to various volt-ampere ratings without difiiculty and thus isadaptable for industrial as well as domestic use.

It is therefore an object of the present invention to provide anelectrical switch utilizing a permanent magnet to selectively retain thecontacts of the switch in the selected position.

It is another object of the present invention to provide an electricalswitch of the novel type described herein with an overload protectiondevice electromechanically connected to the movable contacts of theswitch whereby same breaks the electrical connection to the load circuitin the event a short develops therein.

It is a further object of the present invention to provide an electricalswitch utilizing a novel arrangement of a permanent magnet, an overloadprotective coil, and

connecting elements in such a manner that a load circuit controlled bysaid switch is amply protected against overload conditions at all times.

It is still another object of the present invention to provide anelectrical switch of the novel type as described herein which switch iscompact, silent and efficient in operation, inexpensive to manufacture,and actuated with a minimum of effort.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodiment of the invention isclearly shown.

In the drawings:

Figure 1 is a partial view of the novel switch of the present inventionwith the actuator means removed therefrom for purposes of clarity;

Figure 2 is a sectional side view of the instant invention takensubstantially along the line 22 of Figure 1;

Figure 3 is a sectional end view of the instant invention takensubstantially along the line 3-3 of Figure 1;

Figure 4 is a schematic diagram of the instant invention and shows atypical connection to an external electrical circuit; and

Figure 5 is a perspective view of the novel switch of the presentinvention as adapted for concealed installation in a typical wall, orthe like.

Relating in detail to the drawings, the switch of the present inventionincludes a casing means indicated generally at 20, preferably formed ofdielectric material throughout. Casing supports actuator means whichincludes in general a push button assembly indicated generally at 21 andan armature assembly indicated generally at 22.

Armature assembly includes a dielectric bar 23 pivotally supported tothe casing on a pin 24. A strip of ferrous material 25 is fastened tothe bottom of dielectric bar 23 such that a permanent magnet 26 mountedto the bottom 27 of the casing will hold the right end of armatureassembly downwardly when it is placed in such position by closing theright side 30 of switch 31. When the right side of switch 31 is pushedthe switch pivots about a center 32 whereby metal strip 33 engagescontact carrier 35 and pushes the right end of the armature assemblydownwardly to cause contact between rnoveable contact 36 and stationarycontact 37.

An electromagnet indicated generally at 38 is mounted to the interior ofcasing 20 and includes a winding 39 surrounding a magnetizable core 40.

A switch disengaging means is formed by a moveable element 42 pivotallymounted at 43. Pivoted element 42 is formed of ferrous material so as tobe attracted by core 40 when an electric current, of predeterminedvalue, passes through winding 39 of the electromagnetic means 38.Pivoted element 42 carries an upper finger 45 and a lower finger 46which engage dielectric bar 23 for moving same upwardly when magneticmeans 38 is energized.

Reference is next made to Figs. 1 and 4 for purposes of describing thecircuitry of the present apparatus. A wire 50 connects a load terminal51 with one side of winding 39 and the other side of winding 51 isconnected to a source terminal 53 via wire 55, connection 56, conductorstrip 57, a lower contact 58, an upper contact 59, conductor strip 68,upper contact 36, lower contact 37, metallic conductor strip 38, andsource terminal 53.

As seen in Fig. 4, a load is connected at one side to terminal 51 by awire 61 and on the other side to a source terminal 62 via a wire 63.

In operation, when the right side 30 of push button 21 is depressed,metallic strip 33 engages metallic strip 35 whereby armature assembly 22is moved downwardly to cause engagement between contacts 36 and 37 andcontacts 53 and 59. This connects load 60 with source terminal 53 viaconductor strip 38, contacts 36 and 37, conductor strip 68, contacts 58and 59, conductor strip 57, connection 56, wire 55, winding 39, wire 50,and load terminal 51, Fig. 3, and wire 61, Fig. 4, to load 60.

When an overload occurs at load 60, the current in winding 39 will reacha predetermined value at which the magnetic field through core 40becomes great enough to urge pivot element 42 to the left as viewed inFig. 2. It will be understood that the field strength in core 40 must begreat enough to move element 42 to the left and armature assembly 22upwardly in opposition to the downwardly directed force exerted bypermanent magnet 26.

When a right end of armature assembly 22 is moved upwardly, in responseto an overload at load 60 as described above, points 36 and 37 and 58and 59 will be opened whereby load 60 is disconnected from sourceterminal 53.

When the overload has been eliminated the switch can again be actuatedby depressing the right side of Patented Feb. 9, 1960.

push button 21. The contacts 36 and 37 and 58 and 59 can, of course, atany time be manually opened by depressing the left side 70 of pushbutton 21.

I claim: v I

1. A switch comprising, in combination, casing means formed ofinsulating material; a permanent magnet carried by said casing means;armature means pivotally mounted to said casing intermediate a first endmovable toward and away from said magnet and a second end movable towardand away from said magnet; an actuator pivotally mounted to said casingand including a first end engageable with said first end of saidarmature for moving said first end towards said magnet and a second endengageable with said second end of said armature for moving said secondend towards said magnet; and a pair of contacts one being stationarilymounted to said casing means and the other being mounted to saidarmature means at a location spaced from said pivotal mounting andinsulated therefrom for movement therewith relative to said one contact.

2. A switch comprising, in combination, casing means; armature meanscarried by said casing means and movable between a first position andsecond position, said armature means including a moveable contact;actuator means movably carried by said casing for selectively movingsaid armature means between said first and second positions; astationary contact carried by said casing means for engagement by saidmoveable contact when said armature means is in one of said first andsecond positions; holding means for retaining said contacts inengagement; a source terminal on said casing means for connection withthe potential side of a source of electrical energy; a load terminalcarried by said casing means; a magnetizable core; a Winding surroundingsaid magnetizable core and connected at one end to said moveable contactand at another end to said load terminal; and a moveable elementoperatively associated with said holding means to disengage saidcontacts, said moveable element being actuated by an electric fieldinduced in said magnetizable core when an electric current passingthrough said winding exceeds a predetermined value.

3. A switch comprising, in combination, casing means; armature meanscarried by said casing means and movable between a first position andsecond position, said armature means including a moveable contact;actuator means movably carried by said casing for selectively movingsaid armature means between said first and second positions; astationary contact carried by said casing means for engagement by saidmoveable contact when said armature means is in one of said first andsecond positions; a permanent magnet for holding said armature means ina position where said contacts are in engagement; a source terminal onsaid casing means for connection with the potential side of a source ofelectrical energy; a load terminal carried by said casing means; amagnetizable core; a winding surrounding said magnetizable core andconnected at one end to said moveable contact and at another end to saidload terminal; and a moveable .element operatively associated with saidholding means to disengage said contacts, said moveable element beingactuated by an electric field induced in said magnetizable core when anelectric current passing through said winding exceeds a predeterminedvalue.

4. The switch defined in claim 2 wherein said armature means including apivotal connection with said casing means and said actuator includes apivoted lever having a first arm engageable with said armature means onone side of said pivotal connection and a second arm engageable withsaid armature means on the other side of said pivotal connection.

5. The switch of claim 2 wherein said moveable element is formed by anarm pivoted to said casing and extended to a position adjacent saidcore, said arm including a connection with said actuator means formoving said contacts to an open position.

6. The switch of claim 3 wherein said moveable element is formed by anarm pivoted to said casing and extended to a position adjacent saidcore, said arm including a connection with said armature for moving saidarmature away from said position.

7. The switch defined in claim 1 wherein certain of said first andsecond ends are formed by resilient metal said movable element beingactuated by an electric fieldstrip means.

8. The switch defined in claim 1 wherein said first and second ends ofsaid armature are formed by resilient strip means and said first andsecond ends of said actuator are formed by resilient metal strip means.

9. A switch comprising, in combination, casing means formed ofinsulating'rnaterial; a permanent magnet carried by said casing means;armature means pivotally mounted to said casing intermediate a first endmovable toward and away from said magnet and a second end movable towardand away from said magnet; an actuator pivotally mounted to said casingand including a first end engageable with said first end of saidarmature for moving said first end toward said magnet and a second endengageable with said second end of said armature for moving said secondend toward said magnet; a pair rounding said magnetizable core andconnected at one end to said movable contact and at another end to saidload terminal; and a movable element operatively associated with saidholding means to disengage said contacts,

said first and second ends are formed by resilient metal strip means.

11. The switch defined in claim 9 wherein said first and second ends ofsaid armature are formed by resilientstrip means and said first andsecond ends of said actuator are formed by resilient metal strip means.

References Cited in the file of this patent UNITED STATES PATENTS2,337,001 Ray Dec. 14, 1943- 2,646,478 Euler et a1. July 21, 19532,665,344 Zozulin et al. Ian. 5, 1954 mi A He-

